PoolingClientConnectionManager does not use ClientConnectionOperator#createConnection() method to create new connections

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk@1442566 13f79535-47bb-0310-9956-ffa450edef68
Log 'Connection can be kept alive' debug message only if the connection is known be re-usable

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk@1442567 13f79535-47bb-0310-9956-ffa450edef68